How can I call builtin functions that aren't builtin?

Question

table() has been a standard function in MATLAB since R2013b. As far as I can see from the documentation, there's nothing special about table, compared to sum, cell, struct, or any other builtin function.

However, when I try to run the function using builtin('table',var1,...varN) I get an error saying:

Error using builtin

Cannot find builtin function 'table'

Investigating this further shows that it is in fact not considered a builtin function:

which('cell')
built-in (C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\cell)

which('table')
C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\@table\table.m  % table constructor
|
Not builtin

Investigating further:

which cell2mat
C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\cell2mat.m

which mat2cell
C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\mat2cell.m

which table2array
C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\table2array.m

which struct2cell
built-in (C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\@struct\struct2cell)  % struct method

which cell2struct
built-in (C:\Program Files\MATLAB\R2014b\toolbox\matlab\datatypes\@cell\cell2struct)  % cell method

So, cell is builtin while table is not. cell2struct is builtin while cell2mat is not.

Why is this, and is there a simple way to call overloaded standard functions that aren't considered builtin by MATLAB?

_{If you think the why part is "too broad", please disregard it and jump to the last part of the question.}

Built-ins are generally compiled due to their frequency of use and/or take an undesirable amount of time to run as `*.m` files. There used to be a tech doc somewhere but I can't find it. — sco1, Feb 04 '16 at 14:13
Makes sense =) But wouldn't it make sense to compile `cell2mat` if they compile `cell2struct`? — Stewie Griffin, Feb 04 '16 at 14:19
Maybe. But as is often the case with development, dev teams may have internal knowledge that makes things not as simple as they seem to folks outside. — sco1, Feb 04 '16 at 14:21
@StewieGriffin: [compiled is not always faster](http://stackoverflow.com/questions/20166847/faster-version-of-find-for-sorted-vectors-matlab/20167257#20167257), often used does not mean that it should be compiled. — Daniel, Feb 04 '16 at 14:23
To answer the explicit question, the "simple" method would probably be to use `which` with `cd` and `feval`, similar to what I did [here](http://stackoverflow.com/a/35153710/2748311) — sco1, Feb 04 '16 at 14:23
Yes it does, but once you have a different function called `table` it no longer works. I think this is the interesting use case for such a function. — Daniel, Feb 04 '16 at 14:29
Of course it works, use the `'-all'` flag and parse the returned cell array for the function located in the 'MATLAB' toolbox. — sco1, Feb 04 '16 at 14:32

score 2 · Answer 1 · answered Feb 04 '16 at 14:20

The documentation page for builtin gives a clear definition:

A built-in function is part of the MATLAB executable. MATLAB does not implement these functions in the MATLAB language. Although most built-in functions have a .m file associated with them, this file only supplies documentation for the function.

score 2 · Accepted Answer · answered Feb 04 '16 at 14:36

2

You can find the native function(s) by something like:

allTables = which  ( '-all', 'table' )
allTables(cell2mat(strfind ( allTables, matlabroot )))

Its not fullproof and for some functions (e.g. sum) there are a lot in the root folders...

answered Feb 04 '16 at 14:36

matlabgui

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How can I call builtin functions that aren't builtin?

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